The jobs report came in as expected Friday, with 192,000 new jobs added in March. But for investors, the number to watch is average weekly earnings.

Wall Street will argue today over whether the jobs report was hindered by weather — March was awful across much of the nation — or whether it's still too low to propel the economy meaningfully.

A big gain in jobs is unlikely unless people start spending more. But people won't spend more unless they get more money, and that's not happening. Average hourly earnings for all employees on private nonfarm payrolls edged down by 1 cent in March to $24.30.

"That number is too low," says Phil Orlando, Chief Equity Strategist at Federated Investors. "We have to see that get higher."

At the moment, businesses are under no pressure to raise wages, in large part because there are so many people who could be working, but aren't. Employers are, instead, pushing existing workers harder. The average workweek edged up 34.5 hours, the manufacturing workweek rose by 0.3 hour to 41.1 hours, and factory overtime rose by 0.1 hour to 3.5 hours.

Why does an investor care about wages? Two reasons. First, rising wages will be a good indicator of a growing economy, making consumer goods stocks more attractive. When you get a raise, you go shopping. (Economists call this "pent-up demand," regular people call it "retail therapy.")

The second: When wages do start to rise, you can expect the Fed to start nudging short-term interest rates higher. Why? You need two ingredients for an inflationary wage-price spiral. Consumers have felt price rises, but haven't seen wages increase. If wages heat up too fast, the Fed will move to dampen the party by raising interest rates. By most estimates, that won't happen until 2015.

When it does, you can expect short- to intermediate-term bond funds to get hit the hardest. Bond prices fall when interest rates rise, and much of the Fed-induced rise will be on the short-term side. But the first few bumps by the Fed aren't a good reason to sell stocks. Rising rates are a sign of a growing economy. Typically, stocks don't stumble until the Fed's third rate hike — the old "three steps and a stumble rule." And with rates at zero, it could take more than three steps. When the stock market crashed in 1987, the three-month Treasury bill averaged 6%.